Conventional integrated circuit (IC) packages comprise a single integrated circuit (IC) die, which is also called a “chip.” A multi-chip module (MCM) comprises a plurality of IC chips on a common or shared substrate, all contained within the same protective package. The individual IC chips in an MCM are interconnected by metallic paths formed on the substrate. The IC chips are coupled to terminals on the substrate, which may be coupled to a conventional lead frame with very thin wires. The substrate and lead frame are encapsulated within the protective package.
In some cases, the various IC chips in a conventional MCM may use different power levels. Accordingly, each IC chip in the MCM may be coupled to its own power plane, which is separate from other power planes coupled to the other IC chips in the MCM. According to previously developed techniques, all of the IC chips share a single ground plane on the MCM substrate.
Conceptually, testing of an MCM may be performed at a chip level, a package level or a system level (board level). Conventional testing of MCMs with IC chips, such as IC memory chips, usually occurs at the chip level. That is, each IC chip is manufactured and tested separately prior its incorporation in an MCM. Conventional testing methods may be time-consuming; restricted to simple, non-complex components; and/or require extra components for testing. Package-level testing has not been performed. System-level testing of MCMs is prohibitively expensive.